Recent advances in wireless receiver design make it possible that a wireless node transmits and receives communication signals using overlapping or even identical frequency resources for reception and transmission simultaneously. This type of full duplex, FD, communication is referred to as in-band FD or “true FD” or simply FD communication. In contrast, a wireless node can typically simultaneously transmit and receive radio signals separated in frequency, this latter communication mode is also referred to as (frequency division) “full duplex”, or simply frequency division duplex, FDD, communication.
In the present description, the term FD is used to refer to the in-band FD communication case and FDD to refer to a communication setup that uses separate frequency channels for the transmitted and received radio signals.
Recent studies indicate that FD communication may be able to (up to) double the spectral efficiency, although this upper bound is typically not reachable in practice. FD communication, however, has the potential to increase the spectral efficiency due to the progress in designing self-interference, SI, cancellation receivers that can reach up to 80-90 dB or even higher SI cancellation capabilities.
The transmission modes in FD communication systems can be categorized in terms of the involved nodes and their capabilities. Bidirectional full duplex, BFD, communication involves a pair of FD capable nodes that send and receive signals to one another on the same frequency channel at the same time. In contrast, three-node FD, TNFD, communication is a type of communication in which a FD capable node communicates with two other, not necessarily FD capable, nodes such that the FD capable node transmits and receives signals from/to the non-FD capable nodes on the same frequency channel simultaneously.
Currently, the 3rd Generation Partnership Project, 3GPP, Long Term Evolution, LTE, system defines so called global procedures to enable network nodes, such as eNodeB's, eNB, to exchange information regarding resource utilization, cell-wise load information, handover request, radio link failure, RLF, eNB configuration and other aspects that are of importance for the global operation of a cellular network. This is described in 3GPP Technical specification TS 36.423. To this end, LTE systems use the X2 interface and the X2 application protocol (X2AP) with associated standardized information elements.
For example, one of the functions of the X2AP according to 3GPP TS 36.423 is load management. This function is used by eNB's to indicate resource status, overload and traffic load to each other. Specifically, the Radio Resource Status information element, IE, indicates the usage of the Physical Layer, PHY, Resource Blocks, PRBs, in Downlink, DL, and Uplink, UL, including DL Guaranteed Bit Rate, GBR, usage, non-GBR usage and total PRB usage.
In a telecommunication network having network nodes which are capable of in-band full duplex communication, an increase in interference issues is to be expected. This, because in an FD communication network, nodes and/or User Equipment, UE, may simultaneously transmit and receive signals at the same frequency.
The above referenced interference may manifest itself in different ways. For example, intra-cell interference wherein nodes transmitting signals at the same frequency, in the same cell, at the same time can cause interference at the nodes which are receiving those signals. As such, the probability of increased interference experienced by UE's in the same cell, or in different cells, increases in case of FD communications.